陕甘花楸果实多糖的结构表征及抗氧化活性研究

陕甘花楸(Sorbus koehneana)是我国西北地区特有的灌木之一,主要被用于观赏和制作家具,但对其有效成分的研究却鲜见报道,从而限制了陕甘花楸产业的进一步开发和利用。该研究以陕甘花楸果实为原料,经石油醚脱脂后,采用超声辅助水提醇沉法提取、Sevag法脱蛋白,得到了较纯的花楸果实多糖(SSP),并对其进行结构表征和抗氧化活性研究。结果表明:(1)经苯酚-硫酸法测得多糖纯度为65.8%;FT-IR检测官能团,发现在3 420 cm~(-1)、2 929 cm~(-1)和1 733 cm~(-1)处存在多糖的典型吸收峰;用SEC-LLS测得重均分子量(Mw)为1.739×105,数均分子量(Mn)为5.052×104,多分散系数为3.443,表明分子量分布较为均一;经三氟乙酸酸解、糖腈衍生化等处理及气相-质谱联用法测定SSP的单糖组成,表明SSP由甘露糖、葡萄糖和未知单糖等3种单糖组成,摩尔比为2.2∶1.4∶6.4。(2)体外抗氧化活性实验表明:SSP具有很好的DPPH清除活性、超氧阴离子清除活性以及较强的还原力;当SSP浓度为2 mg·mL-1时,SSP对DPPH自由基的清除能力相当于BHT的96%,对超氧阴离子自由基清除能力为Vc的76.07%,还原能力等价于Vc的92%。以上表明该多糖可以用于抗衰老和抗炎等方面,是一种优良的天然抗氧化剂,为花楸资源的进一步开发利用提供了更为广阔的前景。

Structural characterization and antioxidant activity of polysaccharide in Sorbus koehneana fruit

Sorbus koehneana is one of the shrubs peculiar in Northwest China. It is mainly used for ornamental and making tools. The research on its effective components is rarely reported, which limits the further development and utilization of the industry of S. koehneana. The polysaccharide components in the fruit of S. koehneana were extracted, and their structures and antioxidant activities were studied. Take S. koehneana fruit as materials, use ultrasonic assisted water extraction and alcohol precipitation, and sevage method to remove protein. Thus, we obtained the S. koehneana fruit polysaccharide(SSP). The results were as follows:(1)The polysaccharide content detected by phenol-sulfuric acid method was 65.8%. The functional group was detected by FT-IR and the polysaccharide was observed to have three characteristic peaks of sugar at 3 420 cm^-1, 2 929 cm^-1 and 1 733 cm^-1, whose molecular weight(Mw)was detected by the SEC-LLS was 1.739×10⁵, number average molecular weight(Mn)was 5.052×10⁴ and the polydispersity was 3.443, and uniform molecular weight distribution. Acidolysis of polysaccharides with trifluoroacetic acid, hydroxylamine hydrochloride and acetic anhydride were derivatized. The monosaccharide composition of S. koehneana polysaccharides was determined by GC-MS, and the polysaccharides were composed of three kinds of monosaccharides such as mannose, glucose and unknown monosaccharide, and the molar ratio was 2.2:1.4:6.4.(2)The antioxidant activity tests in vitro showed that the SSP had high scavenging capacity on DPPH, superoxide anion radicals and reducing power. The scavenging capacity of SSP on DPPH radical was 96% of BHT, 76.07% of Vc on superoxide anion radical and 92% of Vc on reduction, while the concentration of SSP was 2 mg·mL^-1. Through this study, we can not only provide theoretical basis for the efficient extraction of polysaccharides from S. koehneana fruits, but also provide a broader prospect for the further development and utilization of S. koehneana resources.